C. U. Shepard—Corundum of N. Carolina and Georgia. 179 
with the margarite and other imbedded minerals. The amphod- 
olite or indianite variety of anorthite also occurs at a few 
or ruby color. Its associates are spinel (which is either red 
or gray), rutile, biotite (phlogopite), a brown hornblende, a 
grass-green arfvedsonite, a peculiar feldspar, and more rarely, 
serpentine). Thus far, neither magnetite nor diaspore have 
been detected as occurring in the aggregate at these places. 
magnetite. But in the absence of quartz and the prevalence of 
Magnesia, we discover a marked similarity of conditions with 
the N. ©. and Chester localities. j 
Concerning the localities in Delaware and Chester counties, 
Pa. Lam unable to speak definitely. But all the specimens of 
corundum I have examined from that 
county, N. C., an entirely distinct region from that in the Blue 
Tidge ‘first described, the corundum is mixed with — 
re rutile. The specimens of blue corundum found within a 
* See this Journal, vol. xi, ix, p. 271. 
